§1.1 Field of the Invention
This invention relates generally to the field of sensors and in particular to biosensors specific to biological/chemical agents and bacterium such as Bacillus anthracis. 
§1.2 Background of the Invention
The potential use of anthrax, and in particular the spores of Bacillus anthracis (BA) as a weapon of biological terrorism has rekindled interest in devices and methods for the rapid detection and identification of biological or chemical agents. Such interest has become particularly acute since the September 11 attacks and the anthrax-by-mail terrorism.
Devices and methods for detecting biological or chemical agents should be rapid, specific, easy to use and transport, and very sensitive since a single pathogenic organism may be an infectious dose in some cases. Consequently, it is important to assess and begin treatment early for individuals exposed to such organisms. Additionally, it is equally important to know whether a person exhibiting general symptoms is suffering from, for example, anthrax exposure, or a less serious ailment for which totally different (or perhaps antagonistic) treatments are indicated.
§1.3 Related Art
Significant technological progress has been made in the detection and analysis of biological and chemical agents over the past decade. (See, for example: Ivnitski, D., Abdel-Hamid, I., Atanasov, P., Wilkins, E. Biosensors Bioelectron., 1999, 14, 599-624 and references therein (875); and Iqbal, S. S., Mayo, M. W., Bruno, J. G., Bronk, B. V., Batt, C. A., Chambers, J. P. Biosensor Bioelectron., 2000, 15, 549-578 and references therein (881).)
The outer face of macromolecular biological assemblies like viruses or bacteria includes a proteinaceous capsid, a membrane composed of glycoproteins and lipids, or a cell wall. Accordingly, they carry charged or chargeable groups on their outer surface creating an electric double layer upon contact with the aqueous phase. (See, for example: Kenndler, E., Blass, D. Trends in Anal. Chem., 2001, 20(10), 543-551; and Lanza, R. P., Langer, R., Chick, W. L. (Eds). When a biological recognition component for bacterial spores, such as a peptides, nucleic acids (See, for example, Park, S.-J, Taton, T. A., Mirkin, C. A. Science, 2002, 295, 1a503-1506.), apatamers (See, for example, Bruno, J. G., Kiel, J. L. Biosensor Bioelectron., 1999, 14, 457-464.), or antibodies (See, for example, Zhou, B., Wirsching, P., Janda, K. D. PNAS, 2002, 99, 5241-5246.) are incorporated in/on a sensing layer of an electrode, the bacterial spores can be recognized by a biospecific reaction which takes place between the biological recognition component and bacterial spores—without any pre-concentration or separation process.
In particular embodiments, bacterial spores (receptor) and peptide, which is fixed on the surface of substrate, associate in solution to form a peptide-spores biological complex. The residual potential due to complementarity between the peptide (the complementary ligand) and the bacterial spores (receptor) with the best possible electrostatic free energy change, is equal in magnitude and opposite in sign to the ligand desolvation potential everywhere within the ligand including on the ligand surface. (See, for example: Honig, B., Nicholls, A. Science, 1995, 268, 1144-1149; Honig, B., Sharp, K., Yang, A.-S. J. Phys. Chem., 1993, 97, 1101-1109; Lee, L.-P., B. Tidor, B. J. Chem. Phys., 1997, 106, 8681-8690; Chong, L. T., Dempster, S. E., Hendsch, Z. S., Lee, L-P., Tidor, B. Protein Sc., 1998, 7, 206-210; and Kangas, E., Tidor, B. J. Chem. Phys., 1998, 109, 7522-7545.) Under the electromotive force (potentiometry), the surface electrostatic potentials of the peptide-spores complex formed relates to the specific biorecognition process enabling bacterial spores to be identified and detected by potentiometry.
Many of the technologies developed and/or currently being used however, such as FT-IR spectroscopy, fluorescence spectroscopy, polymerase chain reaction (“PCR”), flow cytometry, impedimetry, UV resonant Raman spectroscopy, and others, are large, expensive, or require sophisticated, relatively time-consuming, and often extensive analysis procedures.
Accordingly, devices and methods which facilitate the accurate, quick, convenient and inexpensive detection of biological or other chemical agents are of significant scientific and societal interest.
In view of the limitations in the art, a flexible method for selectively detecting a wide range of molecules is needed. Additionally, it is desirable that such methods and devices constructed therefrom be applicable to the detection of biological or other chemical agents.
Such methods and devices are the subject of the instant invention.